This invention relates to hoppers for use with pressurized containers.
Pressurized containers which are frontally sealed at their upper ends by hoppers are known in numerous different constructional forms. In the simplest construction, the pressure container is a cylindrical vessel with a capacity of 100 to 1000 ml and made from aluminium or tin plate. The hopper, i.e. the upper frontal termination or seal, is either an integral part of the vessel or is connected as a separate component to the container body by flanging. The hopper has an opening, which is closed by a disk or plate having a seal. The seal is generally constructed as a manually operable valve, which permits the discharge of the contents as foam, powder, paste or a liquid jet. The pressure container is a completely sealed unit, which eliminates the problem of undesired outflow or atmospheric oxidation of the content. The content essentially comprises a vapour phase as a blowing or foaming agent, a liquid phase constituted by the active substances, the blowing or foaming agent being dissolved in the liquid phase.
Another known type of pressurized container employs a dosed delivery of a number of chemically reactive products, which may only come into contact with one another immediately prior to use. Such a two-component product is e.g. constituted by a polyurethane foam, which is used in many places and ways, e.g. in the building trade for in situ foaming.
The use of pressurized containers for such multicomponent products generally requires the use of larger container voumes. The components are housed in separate partial containers within the pressure container and subject to the action of a gas propellant, optionally using a plunger or piston, which separates the gas propellant filling from the partial containers. However, much higher pressures are required for mixing highly viscous components than in the case of simple pressurized containers.
When higher pressures are needed for multicomponent containers, the pressurized containers must be dimensioned for these higher pressures. When the hopper is manufactured together with the frame or body, this means a relatively complicated solution, because the container body wall thickness would be smaller than that of the hopper. When, as in the case of tin plate pressurized containers, the hopper is made from a separate piece with a greater wall thickness, flanging to the body edge causes problems and in the case of a convex hopper, there is not sufficient space for providing an outlet, e.g. a valve for each partial container, so that special outlets must be designed.